The invention relates to a novel antioxidant. As is well known, fats and oils become rancid or otherwise unpleasant as to flavor or odor by reason of oxidation effects. A number of chemical compounds have been employed for avoiding or reducing these effects, i.e. so that the fats and oils, or foods containing them, may be kept for longer periods of time, but such agents have not been entirely satisfactory or effective in many cases. Furthermore, they are chemical products not derived from or identical with material of natural food classifications, and there has been some question about the advisability of using them.
The most commonly used antioxidants at the present time are BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene). They are added to a wide variety of foods on the market. However, they are quite volatile and easily decomposed at high temperatures. Consequently, they are not satisfactory for such common food products as French fries, potato chips, etc. Furthermore, they are not effective in vegetable oils and in preventing the development of initial off-flavors, such as the reversion flavor. The newly developed TBHQ (tertiary butylhydroquinone) has an excellent ability to retard the absorption of oxygen. However, it does not seem to retard the development of objectionable flavors. Fried noodles stabilized with TBHQ are known to absorb less oxygen than those stabilized with BHT. However, the fried noodles stabilized with TBHQ developed a strong rancidity odor before that observed in the sample stabilized with BHT. It is also known that soybean oil stabilized with TBHQ has a lower peroxide number during storage, but develops a stronger objectionable flavor.
In any event, the commonly used antioxidants today are synthetic chemicals. There is a tendency for the consumers to reject them.
Furthermore, the possible toxicity of the synthetic chemicals used as antioxidants have been a subject of study for many years (Johnson and Hewgill, 1961; Branen, 1975). In an issue of the "Food Chemical News" (1976), the concern of the FDA on the use of BHT was reported. The concern stems from scientific literature reviews conducted for the FDA which focused on the enzyme-inducing effects of BHT on liver and on extraheptic organs, such as the lungs and gastrointestinal tract mucosa. The article also reported that the FDA has expressed an interest in the effect of BHT on the conversion of other ingested materials into toxic substances or carcinogens by the increase of microsomal enzymes. This is certainly nothing new because restrictions have been placed upon the use of such synthetic antioxidants by many European and Asiatic countries.
All this leads to the interest of preparing antioxidants from natural food stuffs by extraction, purification and fractionation. Certainly, there is no assurance whatsoever that a fraction or a compound isolated from natural food is safe. Nevertheless, such an antioxidant would be natural identicals, not a synthetic chemical, but rather a natural component of foods which we have been eating for thousands of years.
It has heretofore been found that antioxidant properties are possessed by certain natural vegetable materials in the class sometimes identified as herbs, and particularly in the specific plants rosemary and sage, which are commonly used as spices. Indeed it has been found that by extracting the fresh or dried leaves or like parts of these plants, such as rosemary, by the use of alcohol or similar readily volatile solvent a somewhat concentrated but crude preparation may be obtained which has considerable antioxidant effect. Procedures have been proposed for making such crude extract, in most instances directly from the leaves, stems or the like of the natural spice, or in some cases by alcohol treatment of the plant material after the oil of the spice (present in very minor proportion) has been substantially removed by steam distillation. The resulting crude extract in alcohol or like liquid has been evaporated (sometimes after some bleaching with active carbon) to yield a solid product. While such product can be considered as in some respect refined in contrast with the original leaves and stems of the spice plant, and indeed although such products have been described as purified and of substantially less taste or odor than the natural spice, these materials have not be any means been fully freed of the characteristically pungent, natural aroma and flavor, with some bitterness, of the basic spice material. Accordingly, although such preparations have been found to provide antioxidant properties, and one such product is currently available on the market, the use of these materials is limited to situations where the basic flavor of the spice is wanted or at least tolerated.
So far as can be ascertained, essentially tasteless and odorless antioxidant materials are limited to substances such as those of the manufactured chemical character mentioned above, and indeed it can be said that there is a real need in the food industry for an antioxidant extracted from natural food stuffs, that has superior properties and can serve a wide range of uses.